Dental articulators are utilized in conjunction with models or castings, the terms being utilized interchangeably herein, in developing prosthodontic dental appliances. In a typical application, a dentist will take an impression of a patient's mouth and utilize this impression to cast a model, which model will be mounted on an articulator to ensure that caps, crowns, bridges or dentures are sized and shaped to coorectly fit in alignment with the remaining piece in the patient's mouth. Dental technicians first fabricate the model and then mount that model on a dental articulator for final finishing and fitting steps.
It is necessary to support such dental models in a relatively natural hinged relationship so as to mimic as closely as possible natural biting movements. If a prosthodontic appliance is not properly shaped, the patient will be forced to undergo multiple adjustments and may possibly damage his or her remaining teeth. A natural bite involves many motions. In addition to normal up and down motions, the human jaw is capable of side to side and back and forth motions, all of which are utilized in eating, drinking and speaking. If a dental articulator cannot simulate all of such motions, the likelihood of fabricating a prosthodontic appliance which will fit comfortably is lessened. Therefore, it is desirable that dental articulators be capable of providing for natural-like jaw movements.
It is also desirable that a dental articulator permit the ready separation of the components of dental models while allowing for their realignment in proper registration. Frequently, it is necessary for dental technicians to perform precise and detailed work on prosthodontic appliances mounted onto dental articulators. If these models are affixed to an articulator which does not permit their separation, such adjustments become very difficult. Accordingly, it will be appreciated that the quality of a prosthodontic appliance will be improved and the quantity of time taken for its production will be decreased if an articulator which allows for separation of the models is employed.
There are a wide variety of dental articulators of varying degrees of sophistication presently available. The most simple of such articulators allow for mere pivotal motion of models relative to one another whereas more sophisticated models provide for a full range of occlusal movement. The simple models of articulators are relatively easy to use, small, lightweight and cheap and frequently are fabricated as disposal items. However, such articulators do not allow for a full range of occlusal motion; furthermore these are permanently attached to the models using plaster or glue, such as cyanoacrylate. In contrast, the more sophisticated articulators are large, complicated and expensive to assemble devices which frequently necessitate precise mounting hardware be affixed to dental models used therewith. Expense is a limiting factor in the use of such articulators insofar as it will be appreciated that a single articulator will be effectively tied up for the entire period of time in which an appliance is being manufactured. To equip a dental laboratory with a sufficient number of such aritculators to enable the output of a high volume of work involves a very considerable expense.
U.S. Pat. No. 4,382,787 discloses a simple, disposable dental articulator. The articulator of the U.S. Pat. No. 4,382,787 is fabricated from a flexible polymeric material and, while the mechanical arrangement of parts of that articulator only allows for simple pivotal motion of dental models, the flexibility of the polymeric material allows for some degree of additional occlusal motion. The articulator disclosed therein is affixed to a pair of dental models by means of ball joints and when proper registration of the models is obtained, the joints are rendered permanently immobile by the injection of an adhesive thereinto. Because of this immobilization, any further adjustment necessitates complete replacement of the articulator. It will additionally be noted that the articulator is essentially destroyed in the process of use and may not be reused.
It will thus be appreciated that there is still a need for a simple, low-cost, reusable dental articulator which readily simulates a full range of occlusal motion and which may be readjusted once affixed to a dental model. It is further desired that such an articulator allow for complete separation of one or both halves of the dental model, and be capable of resisting the stresses imposed by occlusal movements during the fabrication of dental appliances. It is further desired that such an articulator not rely upon the use of plaster or adhesives for affixing the positional relationship of the models attached thereto.
The present invention provides a dental model articulator securing these advantages. The articulator disclosed herein is simple, low in cost, and adjustable over a full range of motion. The articulator includes a pair of joints affixable to the dental models, which joints may be selectively and reversably immobilized so as to allow for adjustment of the articulator during use as well as allowing for removal of the articulator from the model for reuse. Additionally, the articulator of the present invention allows for the ready and reversible separation of the dental castings as well as the replacement of said castings in their previous registration. These and other advantages of the present invention will be readily apparent from the drawings, description, and claims which follow.